Roasting-furnace.



No. 677,510. Patented July 2, I901. B. HALL.

ROASTING FURNACE.

[Application filed Jan. 18, 1901.)

2 Sheets-Sheet l.

- (No Model.)

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No. 677,510. Patented My 2, l90|..

B. HALL.

BOASTING FURNACE.

(Application filed Jan. 18, 1901.) (No Model.) 2 Sheets-Sheet 2.

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BENJAMIN HALL, OF NEVADA CITY, CALIFORNIA.

ROASTiNG-FURNACE.

SPEUEFICATION forming' part of Letters Patent No. 677,510, dated July 2,1901.

Application filed January 18, 1901. Serial No 43,690. (No model.)

To all 2077/0721, it Uta/y concern:

Be it known that L'BENJAMIN HALL, a citizen of the United States,residing at Nevada 'City, county of Nevada, State of California,

have invented an Improvement in Roasting- Furnaces; and I hereby declarethe following to be a full, clear, and exact description of the same.

My invention relates to that type of roasting-furnace known as anautomatic hearth roastingfurnace, in which the roastingchamber consistsof a floor or hearth upon which the ore is automatically charged andspread and wherein the ore is slowly stirred or turned over during theprocess of roasting or burning oil the sulfur and at the same timecarried forward toward the dischargepit by means of rakes or rabbleswhich are attached to carriages moved by endless chain belts or wireropes. As heretofore constructed, these carriages, with the chain beltsor wire ropes, have been located and operated within a supplementalchamber or chambers contiguous to the main roasting-chamber or hearth inorder to protect them from the burningore,said supplemental chambersbeing connected with the roasting-chamber by means of an open slot orslots through which the rabble or rake is connected with thedriving-carriage. The objection to a furnace of this construction isthat the heat, dust, and acids produced from sulfurous gases pass fromthe main roasting-chamber or hearth through the slot connecting with andinto the supplemental chamber, thus submitting the chain belts, wireropes, or other connections and the carriages to a corrosive action,which in a short time destroys them.

The object of my invention is to overcome this objectionable feature,and I accomplish it by entirely eliminating or doing away with thesupplemental chamber and driving the rakes or rabbles by means ofmechanism located outside of the furnace. At the same time I preventcold air from entering the furnace and confining the heat, dust, andgases inside the furnace during the progress of the roasting. This iseffected by mechanism which will be more fully explained by reference totheaccompanying drawings, forming a part of this specification, and inwhich similar characters refer to similar parts in each drawing.

Figure l is a side elevation of the furnace. Fig. 2 is a transversesectional view on the line m a: of Fig. 1.

A is the floor or hearth of the furnace, upon which the ore is spreadand slowly stirred during the roasting or burning off of the sulfur.

B is the arch or top of the furnace.

2 represents iron arch-plates attached to the binder-supports 3, andfrom these plates the shield 4 projects downward, dipping into a troughor water-jacket 5. The space inclosed between these two parallel troughsupon each side and between the floor A and arch 13 forms theroasting-chamber.

6 is a bar extending transversely across the interior of the chamber, towhich are attached small shovel projections 7, and these constitute therakes or rabbles for stirring the ore. The ends of the rake or rabbleare bent into U shape, as shown at 8, and the lower curvatures of thesebent arms pass under the shield 4 and outside of the furnace and areattached to carriages 9. These carriages are connected to the endlesschain belts 10, which receive motion and are driven from the chainwheels or pulleys 11, suitably journaled with relation to the furnace.To these pulleys power is applied by any suitable means through thedriving-shaft, as at 12. The backsta'ys 3 exterior to the furnace notonly serve to carry the arch and the superstructure, but they carry alsothe rollers 13, upon which the carriages 9 run.

The small rollers 14 are so located as to carry and hold up the endlesschain belts 10, which are quite long and have a tendency to sag.

15 is the fire-box, through which heat is supplied to the furnace, and16 is a pit orreceptacle into which the roasted ore 'is' automaticallydischarged by the rakes or rabbles.

17 is a flue connecting with the chimney, through which the fumes andgases pass from the roasting-chamber to the open air.

18 18 are two hinged doors that automatically open to allow the rakes orrabbles to enter and to leave the furnace.

19 is a pipe by means of which a continuous stream of cold water isintroduced into the trough or water-jacket 5, and 20 is anoverflow-pipe, allowing the heated water to escape from the trough orjacket, thus providing a continuous circulation.

21 is an incline upon which the ore to be roasted is automatically fedby means of any suitable feeder, and the ore is carried into the furnaceand spread upon the hearth by the rakes or rabbles which engage it. p

The operation of the furnace is as follows: The trough or water-jacket 5is filled with water to the proper depth to form a perfect seal andclosure of the channel between the water-jacket and the outside of thefurnace. The fuel in the firebox-15 is ignited, the furnace heated up,and power is applied to the driving-shaft, thus setting in motion thechain-wheels 11, the endless chain belts 10, the carriages 9, and therakes or rabbles 6 7. Ore is fed upon the incline 21 and is carried intothe roasting-chamber, spread upon the hearth, subjected to the action ofthe heat from the fire-box, and is gradually stirred and carried forwardby the action of the rakes or rabbles, which make successive passagesthrough the furnace and overthe hearth until the ore is finally roasted,the sulfur being driven off, after which the ore is discharged into thepit 16, from which it may be removed as desired.

The special feature of this furnace is the method employed to drive therakes or rabbles by means of endless chain belts and rabblecarriageslocated outside the furnace, while at the same time confining the heat,dust, and furnace-gases entirely within the roasting chamber andpreventing the entrance of air. I

V referring to the drawing of cross-section of the furnace as shown inFig. 2 it will be clearly seen that a perfect seal is maintained at alltimes during the passage of the rakes or rabbles through the furnace bymeans of the fluid within the trough or jacket and thedownwardly-projecting shield, which leaves a sufficient space beneath itthrough which the U- shaped arm 8 of the rabbles pass while beingimmersed in and surrounded by the fluid. By this method the endlesschain belts and carriages are entirely removed from the corrosive actionof the heat, dust, and acids produced from sulfurous or other fumes, andI thus effect a great saving in these parts, which will if properlyconstructed last indefinitely without renewal.

The novelty in my invention which I desire to claim, broadly, is themethod of driving the rakes or rabbles from the outside of the furnace,where the parts will be entirely free from the corrosive action of theburning sulfur, and preventing the cold air from gaining admission tothe roasting-chamber and confining the heat, dust, and gases within thefurnace by means of a seal, While the stirring of the ore is effected bythe passage of the rabbles over the floor or hearth during the operationof roasting:

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. A hearth roasting-furnace, rakes or rabbles operating therein,driving mechanism located outside the furnace walls, and connected withthe rakes or rabbles, and means inclosing the connections and forming amobile seal in the side walls of the furnace whereby the heat and gasesare confined within, and cold air prevented from entering the furnace,during the passage of the rakes or rabbles through the ore and over thehearth of said furnace. f

2. In combination with an ore-roasting furnace having openings in itsside walls, rakes or rabbles within said f u rnace,a driving mechanismexterior to the furnace-wallsand conne'cting through the openings withthe rakes or rabbles, and means forming a liquid seal for said openingswhereby the heat, dust and gases, are confined within theroasting-chainber, while permitting the rakes or rabbles to be operatedthrough said openings. 7

3. In an ore-roasting furnace, a chamber having stirrers or scrapersadapted to move over the floor of the furnace, tracks parallel with andexterior to the furnace, trucks or carriages mounted and movable uponsaid tracks, arms connecting the exterior trucks with the interiorstirrers, troughs or channels between the trucks and furnace-chambercontaining a substance which will form a seal, and plates centrallydisposed with reference to the troughs and dipping into the containedsubstance, the arms connectin g the carriage with the stirrers beingbent so as to dip into the substance in the troughs, whereby a seal iseifected.

4. In an ore-furnace, an ore-chamber having stirrers or scrapers bywhich the ore is stirred and advanced, troughs or channels formedexterior to the furnace, with depending plates'extending centrally intosaid charinels, a substance placed within said channels to cover thedepending plate and form aseal therewith, tracks exterior to thefurnace, carriages adapted to travel upon said tracks, and arms havingone end connected with the carriage and the other with the stirrers orscrapers, said arms being bent 'so as to dip into the sealing-channelsand pass beneath the depending plates.

5. A horizontal ore-furnace having traveling stirrers or scrapersmovable through said furnace, carriages exterior to the furnace, meansfor operating the carriages, connec tions between said carriages and thestirrers whereby they are moved in unison, and troughs in the side wallsof the furnace and containing a sealing substance to prevent the ingressor egress of hot or cold air or vapor, the connections between thecarriages and the stirrers being bent to pass through the sealingmaterial in the channels.

6. Aroastingordesulfurizing furnace, having a trough in its side wallsprovided with sealing material, a scraper or stirrer adapted to moveover the furnace-hearth, an arm ex tending from said scraperand passingthrough the sealing material, and driving means exterior to the furnaceconnected to the arm for moving the scraper over the hearth, substantially as set forth.

7. A roasting-furnace having rakes or rabbles movable over thefurnace-floor, carrying devices exterior to the furnace, connectionsbetween said devices and the rakes, and troughs in the side walls of thefurnace and containing a mobile substance forming a continuous sealthrough which the connectingarms move, and depending plates, the loweredges of which dip into the sealing substance above the line of travelof the arms.

8. In combination with an ore-roasting furnace having openings in itsside walls, rakes or rabbles within said furnace, a driving mechanismexterior to the furnace-walls and connecting through the openings withthe rakes or rabbles, means forming a liquid seal for said openings,whereby the heat, dust and gases, are confined within theroasting-chamber, while permitting the rakes or rabbles to be operatedthrough said openings, and means by which the sealing liquid is removedand circulated.

9. A horizontal furnace having upper and 'lower portions of the sidewalls made rigid,

